Significance of renal rim grade on computed tomography in severity evaluation of acute pancreatitis

Pancreatic Ischemia-Reperfusion Injury Following Endovascular Treatment of Symptomatic Celiac and Superior Mesenteric Artery Stenosis

CLINICAL IMPACT

With endovascular therapy becoming the first-line treatment for symptomatic chronic mesenteric ischemia, acute pancreatitis within the context of abdominal ischemia-reperfusion injury may be seen more often in cross-sectional imaging following this kind of interventions and should therefore be kept in mind by the reading physician.

The Involvement of Renal Capsule Is Associated With Acute Kidney Injury in Patients With Acute Pancreatitis

Background: Acute pancreatitis (AP) is characterized by pancreatic/peripancreatic inflammation. Involvement of renal capsule refers to peripancreatic inflammation extending beyond the Gerota fascia and disappearance of renal rim sign (+) on CT images. However, its association with acute kidney injury (AKI), an important complication of AP, was rarely studied. Aim: This study aimed to assess the relationship between the involvement of renal capsule and AKI in a cohort of patients with AP. Methods: We retrospectively screened all the patients admitted for AP from January 2018 to December 2019. The involvement of renal capsule was judged by experienced radiologists according to the CT imaging. Propensity score matching (PSM) was used to control for biases in group sizes and baseline characteristics. The primary outcome was the development of AKI during the index admission. We also categorized the pararenal inflammation with the renal rim grade (RRG) and compared the incidence of AKI among different grades. Results: Involvement of renal capsule was identified in 71 of 503 patients (14.1%). The incidence of AKI was significantly higher in these patients when compared with the matched controls (43/71, 60.6% vs. 12/71, 16.9%, p < 0.001). Moreover, mortality also differed between groups (12.7% vs. 1.4%, p = 0.017). Multivariable logistic regression showed that renal capsule involvement is an independent risk factor of AKI (odds ratio, 4.355; 95% confidence interval, 1.434, 13.230, p = 0.009). Patients with RRG grade III had a significantly higher incidence of AKI than the other two grades (60.6% for Grade III, 17.1% for Grade II, and 3.8% for Grade I, p < 0.001). Conclusion: Involvement of renal capsule is associated with higher AKI incidence and mortality.

Development and validation of a computed tomography index for assessing outcomes in patients with acute pancreatitis: "SMART-CT" index

PURPOSE

The existing CT indices do not allow quantitative prediction of clinical outcomes in acute pancreatitis (AP). The aim of this study was to develop and validate a revised CT index using a nomogram-based approach.

METHODS

This retrospective study comprised consecutive patients with AP who underwent contrast-enhanced CT between June 2017 and March 2019. 123 CT scans were randomly divided into training (n = 103) and validation groups (n = 20). Two radiologists analyzed CT scans for findings described in modified CT severity index and additional exploratory items (13 items). Seven items (pancreatic necrosis, number of collections, size of collections, ascites, pleural effusion, celiac artery involvement, and liver steatosis) found to be statistically significant were used for development of index. Synthetic minority oversampling technique (SMOTE) was employed to balance representation of minority classes and hence this index was named "SMOTE Application for Reading CT in AcuTe Pancreatitis (SMART-CT index)". Binomial logistic regression was used for development of prediction algorithm. Nomograms were then created and validated for each outcome.

RESULTS

The new CT index had area under the curve (AUC) of 0.79 [95% CI 0.65-0.93], 0.66 (95% CI 0.54-0.77), 0.75 (95% CI 0.65-0.85), 0.83 (95% CI 0.69-0.96), 0.70 (95% CI 0.60-0.81), and 0.64 (95% CI 0.53-0.75) for mortality, intensive care unit (ICU) stay, length of hospitalization, length of ICU stay, number of admissions, and severity, respectively. The AUC of validation cohort was comparable to the training cohort.

CONCLUSION

The novel nomogram-based index predicts occurrence of clinical outcome with moderate accuracy.

Potential role of imaging for assessing acute pancreatitis-induced acute kidney injury

Acute kidney injury (AKI) is a common complication of acute pancreatitis (AP) that is associated with increased mortality. Conventional assessment of AKI is based on changes in serum creatinine concentration and urinary output. However, these examinations have limited accuracy and sensitivity for the diagnosis of early-stage AKI. This review summarizes current evidence on the use of advanced imaging approaches and artificial intelligence (AI) for the early prediction and diagnosis of AKI in patients with AP. CT scores, CT post-processing technology, Doppler ultrasound, and AI technology provide increasingly valuable information for the diagnosis of AP-induced AKI. Magnetic resonance imaging (MRI) also has potential for the evaluation of AP-induced AKI. For the accurate diagnosis of early-stage AP-induced AKI, more studies are needed that use these new techniques and that use AI in combination with advanced imaging technologies.

The Value of Modified Renal Rim Grade in Predicting Acute Kidney Injury Following Severe Acute Pancreatitis

OBJECTIVE

To retrospectively determine the value of modified renal rim grade (MRRG) in predicting acute kidney injury (AKI) in the early phase of severe acute pancreatitis (SAP).

METHODS

This institutional review board-approved retrospective study included patients with SAP who underwent abdominal contrast-enhanced computed tomography (CT) within 48 hours after disease onset. Modified renal rim grade, renal rim grade, CT severity index, modified CT severity index, extrapancreatic inflammation on CT scores, and posterior pararenal (PPR) space involvement were assessed. Clinical data, including bedside index of severity in acute pancreatitis and New Japanese Severity Scoring system scores, were collected. Primary end points were AKI and mortality. Scores were evaluated by receiver operating characteristic curve analysis. Correlational analyses between MRRG scores and the other scores were performed with Spearman analysis.

RESULT

One hundred five consecutive patients were enrolled in our study. The areas under the curve (AUCs) of MRRG in predicting AKI (0.90) and mortality (0.83) were comparable to extrapancreatic inflammation on CT (0.89 and 0.85, P > 0.05) and were higher than those of the other CT scores (P < 0.05). Modified renal rim grade score of greater than 4 yielded sensitivities and specificities of 81% and 89% for predicting AKI and 88% and 66% for mortality. Modified renal rim grade correlated moderately with bedside index of severity in acute pancreatitis (Spearman r = 0.47) and New Japanese Severity Scoring system (r = 0.43) scores. Besides, the prevalence of PPR space involvement in nonrecovery AKI patients was higher than that in recovery patients (94% vs 36%, P < 0.05).

CONCLUSIONS

Modified renal rim grade is well correlated with the occurrence of AKI and mortality in SAP. The PPR space involvement is a promising prognostic factor for nonrecovery of AKI in SAP patients.

Extra-pancreatic necrosis alone: Contours of an emerging entity

Acute pancreatitis is of two morphologic types: interstitial edematous pancreatitis that is not associated with any tissue necrosis and necrotizing pancreatitis wherein the pancreatic parenchyma with or without varying amount of extra-pancreatic tissue/fat undergoes necrosis. Necrotizing pancreatitis has a worse outcome compared with interstitial pancreatitis because of increased severity related to a heightened systemic response and cytokine storm associated with tissue necrosis. Increasingly, an entity of extra-pancreatic necrosis (EPN) alone, wherein the pancreatic parenchyma is normal on an enhanced computed tomographic scan but the peri-pancreatic tissues undergo necrosis, is being recognized. Available data suggest that the outcomes in patients with EPN alone are between the excellent prognosis of patients with interstitial and adverse prognosis of patients with necrotizing pancreatitis. The extent of EPN also seems to determine the outcome. This review summarizes the currently available literature on this entity and various radiological scores that have been suggested to determine the presence and stage of EPN.

Comparative evaluation of blood markers and extrapancreatic inflammatim on CT score in the early prediction of the severity of acute panereatitis

AIM: To compare the value of blood markers and extrapancreatic inflammation on CT score (EPIC) in early prediction of the severity of acute pancreatitis (AP).

METHODS: The clinical, laboratory and CT data obtained on admission (within 24 h of hospitalization) for 96 patients with AP who were hospitalized from September 2010 to September 2011 were analyzed. Severe AP (SAP) was defined as the presence of one or more of the following signs: mortality, persistent organ failure and/or admission ICU, and/or operation. Blood markers and EPIC were compared between SAP group and mild AP (MAP) using the t test. The correlation between blood markers, EPIC and severity of AP was analyzed. The value of blood markers and EPIC in predicting the severity of AP was assessed using receiver operation curve analysis. The sensitivity, positive predictive value and accuracy were also studied.

RESULTS: There were 20 patients with SAP and 76 patients with MAP. The levels of blood markers and EPIC in the SAP group were significantly higher than those in the MAP group [white blood cell (WBC): (15.16 ± 5.06) × 10⁹/L vs (11.05 ± 1.76) × 10⁹/L, neutrophil-lymphocyte ratio (NLR): 18.95 ± 12.13 vs 6.63 ± 3.44, high-sensitivity C-reactive protein (hs-CRP): 58.35 mg/L ± 20.47 mg/L vs 28.59 mg/L ± 12.92 mg/L, D-dimer (DD): 1596.95 μg/L ± 1409.05 μg/L vs 412.52 μg/L ± 316.66 μg/L, EPIC: 3.30 ± 0.86 vs 1.50 ± 0.96, all P = 0.000]. The Spearman correlation coefficients (rs) between severity of AP and WBC, NLR, hs-CRP, DD and EPIC were 0.419, 0.571, 0.568, 0.434 and 0.613, respectively (all P = 0.000). The area under the curve (AUC) of WBC, NLR, hs-CRP, DD and EPIC in predicting the severity of AP were 0.798 (0.670-0.925), 0.906 (0.830-0.981), 0.904 (0.838-0.970), 0.808 (0.638-0.938) and 0.917 (0.851-0.983), respectively. The predictive sensitivities were 70.00%, 85.00%, 85.00%, 75.00% and 85.00%; the positive predictive values were 58.33%, 73.91%, 51.52%, 48.39% and 72.00%; and the accuracies were 83.33%, 90.63%, 80.21%, 78.13% and 90.63%, respectively.

CONCLUSION: WBC and DD have a moderate value in predicting the severity of AP, while NLR, hs-CRP, and EPIC have a much higher value.